JP3141536B2 - Printing ink binder - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a binder for printing inks.

[0002]

2. Description of the Related Art In recent years, various plastic films have been developed as packaging materials in accordance with the complexity of packaging contents and the advancement of packaging technology. As a result, plastic films suitable for the contents have been appropriately selected. Has come to be used. Along with this, high performance has also been required for printing inks used for decoration or surface protection of plastic films.

Conventionally, polyurethane resins have been widely used as binders for such printing inks. Generally, a printing ink using a polyurethane resin as a binder has excellent adhesive strength alone to polyester and nylon films, but does not have sufficient adhesive strength to general-purpose films such as polyethylene and polypropylene films.

[0004] In view of the above disadvantages, polyurethane resins have been used as two-pack reactive inks containing not only polyisocyanate compounds but also polyisocyanate compounds. However, the two-pack reaction type ink is disadvantageous in that a curing agent must be blended immediately before printing, handling is inconvenient, and furthermore, there is a practical limitation in terms of pot life (pot life). .

[0005] Therefore, in the art, it can be used as a one-part ink which does not need to be blended with a polyisocyanate compound.
In addition, various polyurethane resins having good adhesion to various plastic films are being researched and developed.

As described above, various one-component inks having good adhesiveness have been developed, and the problem of the adhesiveness has been solved to some extent. When used for printing a plastic film used as a packaging base material through a sterilization step, there is a disadvantage that the boil resistance and the retort resistance are still inferior. Therefore, in the field where boil resistance and retort resistance are required, the one-pack type ink is difficult to use, and despite the above-mentioned problems, the two-pack reaction type ink containing a polyisocyanate compound still occupies the mainstream. That is the current situation.

[0007]

The present invention can be used as a one-pack type printing ink having excellent adhesion and boil resistance to various types of plastic films such as polyester, nylon, polyethylene, polypropylene, etc., as printing materials. It is an object to provide a binder for printing ink.

[0008]

Means for Solving the Problems In view of the above technical background, the present inventors have made intensive studies to solve the problems of the prior art, and as a result, have printed a polyurethane resin having a specific functional group in the molecule. The inventors have found that the above problem can be solved by using the ink as a binder for ink, and have completed the present invention.

That is, the present invention provides a polymer polyol,
In a binder for a printing ink containing a polyurethane resin as a main component obtained by reacting a diisocyanate compound, a chain extender and, if necessary, a chain length terminator, the polyurethane resin has an oxazolinyl group and / or a derivative of an oxazolinyl group. The present invention relates to a printing ink binder.

The constituent components of the polyurethane resin which is the main binder of the present invention are as follows. First, as the high molecular polyol component, ethylene oxide, propylene oxide, polyether polyols such as polymers or copolymers such as tetrahydrofuran; ethylene glycol, 1,2-
Propanediol, 1,3-propanediol, 1,3
-Butanediol, 1,4-butanediol, neopentyl glycol, pentanediol, 3-methyl-1,
Various known saturated and unsaturated low molecular weight glycols such as 5-pentanediol, hexanediol, octanediol, 1,4-butynediol, diethylene glycol, triethylene glycol and dipropylene glycol, or n-butyl glycidyl ether; Alkyl glycidyl ethers such as ethylhexyl glycidyl ether, monocarboxylic acid glycidyl esters such as versatic acid glycidyl ester, dimer diol obtained by reducing dimer acid, and adipic acid, phthalic anhydride, isophthalic acid, terephthalic acid, and maleic acid. Acid, fumaric acid, succinic acid, oxalic acid, malonic acid, glutaric acid, pimelic acid, suberic acid, azelaic acid, dibasic acid such as sebacic acid or the corresponding acid anhydride or dimer acid, etc. Polyester polyols obtained by ring-opening polymerization of cyclic ester compounds; other polyols such as polycarbonate polyols, polybutadiene glycols, and glycols obtained by adding ethylene oxide or propylene oxide to bisphenol A; Various known polymer polyols generally used for the production of polyurethane are exemplified.
Among the above, in the case of a high molecular polyol obtained from a glycol and a dibasic acid, up to 5 mol% of the glycol component can be replaced with the following various polyols. That is, for example, glycerin, trimethylolpropane, trimethylolethane, 1,2,6-hexanetriol, 1,2,4-butanetriol, pentaerythritol, sorbitol and the like can be exemplified.

[0011] The molecular weight of the above-mentioned various polymer polyols is
It is appropriately determined in consideration of the solubility, drying property, blocking resistance and the like of the obtained polyurethane resin, and is usually 500 to 6
000 is preferable. If the molecular weight is less than 500, the printability tends to be inferior due to the decrease in solubility, while if it exceeds 6000, the drying property and the blocking resistance tend to decrease.

The diisocyanate compound which is another component of the polyurethane resin of the present invention includes aromatic, aliphatic and alicyclic diisocyanates. For example, 1,5-naphthylene diisocyanate, 4,4′-
Diphenylmethane diisocyanate, 4,4'-diphenyldimethylmethane diisocyanate, 4,4'-dibenzyl isocyanate, dialkyldiphenylmethane diisocyanate, tetraalkyldiphenylmethane diisocyanate, 1,3-phenylene diisocyanate,
1,4-phenylene diisocyanate, tolylene diisocyanate, butane-1,4-diisocyanate, hexamethylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, 2,4,4-trimethylhexamethylene diisocyanate, lysine diisocyanate, cyclohexane- Typical examples thereof include 1,4-diisocyanate, xylylene diisocyanate, isophorone diisocyanate, dicyclohexylmethane-4,4'-diisocyanate, 1,3-bis (isocyanatomethyl) cyclohexane, methylcyclohexane diisocyanate, dimer diisocyanate, and the like. . These isocyanates may be used alone or in combination of two or more.

As the chain extender, polyamines such as ethylenediamine, propylenediamine, hexamethylenediamine, diethylenetriamine, triethylenetetramine, isophoronediamine, dicyclohexylmethane-4,4'-diamine and dimerdiamine can be used.
Further, in the molecule of 2-hydroxyethylethylenediamine, 2-hydroxyethylpropylenediamine, di-2-hydroxyethylethylenediamine, di-2-hydroxyethylpropylenediamine, 2-hydroxypropylethylenediamine, di-2-hydroxypropylethylenediamine, etc. Diamines having a hydroxyl group and the above-mentioned low molecular weight glycols can also be used as a chain extender.
As the chain terminating agent used if necessary, di-
Dialkylamines such as n-butylamine, dihydroxyalkylamines such as diethanolamine, and alcohols such as ethanol and isopropyl alcohol can be used.

The oxazolinyl group and / or the derivative of the oxazolinyl group introduced into the polyurethane are represented by the following general formula (1):

	

Embedded image

(R ¹ and R ² are a hydrogen atom, a halogen atom,
An alkyl group having 1 to 20 carbon atoms, a halogenated alkyl group,
An oxyalkyl group, a phenyl group, or a group in which R ¹ and R ² are bonded to form an alkylene group having 3 to 10 carbon atoms; R ³ is an amino group, a phenylamino group,
Shows a put group. )) Can be exemplified. Examples of the compound having such an oxazolinyl group and / or a derivative of the oxazolinyl group include 2-amino-2-oxazoline, 2-phenylamino-2-oxazoline, 2-amino-5-methyl-2-oxazoline,
2-amino-4,5-cyclotetramethylene-2-oxazoline, 2-amino-4,5-diphenyl-2-oxazoline, 2-amino-5-chloromethyl-2-oxazoline, 2-amino-5-oxymethyl -2-oxazoline, 2-mercapto-2-oxazoline and the like. By using the compound instead of the above-mentioned chain terminator or in combination with the above-mentioned chain terminator, an oxazolinyl group and / or oxazolinyl is obtained. Derivatives of the group can be incorporated into the molecule of the polyurethane resin. Also, by reacting the compound after synthesizing the polyurethane resin, the oxazolinyl group and / or the derivative of the oxazolinyl group can be incorporated into the molecule of the polyurethane resin.

The binder for printing ink of the present invention comprises:
The oxazolinyl group and / or the derivative of the oxazolinyl group are not limited to those introduced into the polyurethane resin by the above-mentioned method, and are not particularly limited as long as the polyurethane resin has the oxazolinyl group and / or the oxazolinyl group derivative in the polyurethane resin. Can be used without restrictions.

The oxazolinyl group and / or the derivative of the oxazolinyl group incorporated in the polyurethane resin undergoes a cross-linking reaction after a drying step after printing, so that a one-part solution which cannot be solved at all by a conventional printing ink binder. It is considered that the boil resistance, retort resistance, etc. of the mold printing ink can be improved.

The content of the oxazolinyl group and / or the derivative of the oxazolinyl group in the polyurethane resin is from 1 × 10 ^-6 to 1 × 10 ⁶ per 1 g of the solid content of the polyurethane resin.
Preferably it is in the range of about ^-3 gram equivalents. When the content is less than 1 × 10 ⁻⁶ gram equivalent, the adhesion to a polypropylene film or the like with one liquid, the boil resistance, etc. are insufficient, and conversely, the content is more than 1 × 10 ⁻³ gram equivalent. In this case, the viscosity stability with time of the solution tends to decrease, which is not preferable.

In the method for producing the polyurethane resin of the present invention, first, a polymer polyol component and a diisocyanate compound are reacted under an excess of isocyanate groups.
A two-step method of preparing a prepolymer having isocyanate groups at both ends of the polymer polyol, and then reacting the prepolymer with a chain extender and, if necessary, a chain terminator in a suitable solvent, and a polymer polyol component, Any one-step method in which a diisocyanate compound, a chain extender and, if necessary, a polymerization terminator are reacted at once in a suitable solvent may be employed, but the former method is preferred for the purpose of obtaining a uniform polymer solution. . In these production methods, as a solvent used, aromatic solvents such as benzene, toluene, and xylene which are well known as solvents for printing inks; ester solvents such as ethyl acetate and butyl acetate; methanol, ethanol, Alcohol solvents such as isopropanol and n-butanol; acetone, methyl ethyl ketone,
A ketone solvent such as methyl isobutyl ketone may be used alone or as a mixture of two or more.

When the polyurethane resin used in the present invention is produced by a two-step method, the conditions for reacting the high molecular polyol component with the diisocyanate compound are not limited except that the isocyanate excess is used. It is preferable to carry out the reaction so that the groups have an equivalent ratio in the range of about 1 / 1.2 to 1/3. The conditions for reacting the obtained prepolymer with a chain extender and, if necessary, a chain length terminator are as follows, assuming that the free isocyanate group at the terminal of the prepolymer is 1 equivalent.
The total equivalent of active hydrogen capable of reacting with the isocyanate group in the chain extender is preferably in the range of about 0.5 to 2.0 equivalents.
It should be within the range of 5 to 1.3 equivalents). When the active hydrogen is less than 0.5 equivalent, the drying property, blocking resistance, and film strength are not sufficient, and when the active hydrogen exceeds 2.0 equivalents, the chain extender remains unreacted. It remains and odor tends to remain after printing.

The number average molecular weight of the polyurethane resin obtained as described above is preferably in the range of about 5,000 to 100,000. When the molecular weight is less than 5000, the drying properties, blocking resistance, film strength, oil resistance, etc. of the printing ink using this as a binder are poor,
On the other hand, when it exceeds 100,000, the viscosity of the polyurethane resin solution tends to increase and the gloss of the printing ink tends to decrease.

The resin solid content concentration of the polyurethane resin solution obtained as described above is not particularly limited, and is appropriately determined in consideration of workability at the time of printing, and is usually 15 to 60% by weight. The viscosity is usually 50 to 10,000 cP / 2
A temperature of 5 ° C. is practically suitable.

In order to produce a printing ink composition using the polyurethane resin of the present invention, a coloring agent, a solvent, and, if necessary, a surfactant and a wax for improving the fluidity of the ink and the surface film are added to the polyurethane resin. May be appropriately blended and kneaded using an ordinary ink production apparatus such as a ball mill, an attritor, and a sand mill. In addition, nitrocellulose, vinyl chloride-vinyl acetate copolymer, polyamide, acrylic resin, chlorinated polypropylene, and the like may be blended without departing from the performance of the present invention.

[0025]

EXAMPLES Hereinafter, the present invention will be described in detail with reference to Production Examples, Examples and Comparative Examples, but the present invention is not limited to these Examples. In each example, all parts and percentages are by weight unless otherwise specified.

Production Example 1 A round-bottom flask equipped with a stirrer, a thermometer and a nitrogen gas inlet tube was charged with 1,000 parts of poly (1,2-propylene adipate) glycol having a molecular weight of 2,000 and 222 parts of isophorone diisocyanate, and then charged under a nitrogen stream. Was reacted at 100 ° C. for 6 hours to obtain a prepolymer having a free isocyanate value of 3.36%, and 815 parts of methyl ethyl ketone was added thereto to obtain a uniform urethane prepolymer solution. Then, in the presence of a mixture consisting of 74.2 parts of isophoronediamine, 9.0 parts of 2-amino-2-oxazoline, 1215 parts of methyl ethyl ketone, and 1015 parts of isopropyl alcohol, 2037 parts of the urethane prepolymer solution was added, and 50 ° C. For 3 hours. The polyurethane resin solution A thus obtained had a resin solid content concentration of 30% and a viscosity of 520 cP / 25 ° C. The number average molecular weight of the polyurethane resin was 25,000.

Production Example 2 In the same reactor as in Production Example 1, poly (1,2-propylene adipate) glycol 1000 having a molecular weight of 2,000 was added.
And a mixture of isophorone diisocyanate and 222 parts of isophorone diisocyanate. The mixture was reacted at 100 ° C. for 6 hours under a nitrogen stream to obtain a prepolymer having a free isocyanate value of 3.36%, and 815 parts of methyl ethyl ketone was added to obtain a uniform urethane prepolymer solution. Then isophorone diamine 74.2
Parts, di-n-butylamine 13.3 parts, 2-amino-
In the presence of a mixture consisting of 0.4 part of 4,5-diphenyl-2-oxazoline, 1223 parts of methyl ethyl ketone, and 1019 parts of isopropyl alcohol, 2037 parts of the urethane prepolymer solution was added and reacted at 50 ° C. for 3 hours. The polyurethane resin solution B thus obtained had a resin solid content of 30% and a viscosity of 650 cP / 25 ° C. The number average molecular weight of the polyurethane resin is 25.
000.

Production Example 3 In a reaction apparatus similar to that of Production Example 1, 1000 parts of poly (butylene adipate) glycol having a molecular weight of 2,000 and 222 parts of isophorone diisocyanate were charged and reacted at 100 ° C. for 6 hours in a nitrogen stream to obtain a free isocyanate value of 3 .4
A 0% prepolymer was obtained, and 815 parts of methyl ethyl ketone was added thereto to obtain a uniform urethane prepolymer solution. Then, 49.3 parts of isophoronediamine, 14.5 parts of 2-hydroxyethylethylenediamine, 15.1 parts of di-n-butylamine, and 2-amino-5-methyl-2-
1.3 parts of oxazoline, 198 parts of methyl ethyl ketone,
1013 parts of toluene and 10 parts of isopropyl alcohol
2037 parts of the urethane prepolymer solution was added in the presence of a mixture consisting of 13 parts, and reacted at 50 ° C. for 3 hours. The polyurethane resin solution C thus obtained had a resin solid content concentration of 30% and a viscosity of 820 cP / 25 ° C. The number average molecular weight of the polyurethane resin is 2000
It was 0.

Production Example 4 In a reaction apparatus similar to that of Production Example 1, 1,000 parts of poly (butylene adipate) glycol having a molecular weight of 2,000 and 222 parts of isophorone diisocyanate were charged and reacted at 100 ° C. for 6 hours under a nitrogen stream to obtain a free isocyanate value of 3 .4
A 0% prepolymer was obtained, and 815 parts of methyl ethyl ketone was added thereto to obtain a uniform urethane prepolymer solution. Then, 72.9 parts of isophoronediamine, 15.2 parts of 2-amino-5-oxymethyl-2-oxazoline,
In the presence of a mixture consisting of 204 parts of methyl ethyl ketone, 1019 parts of toluene and 1019 parts of isopropyl alcohol, 2037 parts of the above urethane prepolymer solution was added and reacted at 50 ° C. for 3 hours. The polyurethane resin solution D thus obtained had a resin solid concentration of 30% and a viscosity of 730 cP / 25 ° C. The number average molecular weight of the polyurethane resin was 20,000.

Production Example 5 In a reactor similar to that of Production Example 1, 1,000 parts of polyoxytetramethylene glycol having a molecular weight of 1,000 and 333 parts of isophorone diisocyanate were charged, and 10
The mixture is reacted at 0 ° C. for 10 hours to give a free isocyanate value of 3.10.
% Prepolymer, and this is added to methyl ethyl ketone 8
89 parts were added to obtain a uniform urethane prepolymer solution. Then, the urethane prepolymer solution 2222 was added in the presence of a mixture consisting of 53.1 parts of isophoronediamine, 50.3 parts of 2-amino-4,5-cyclotetramethylene-2-oxazoline, 1345 parts of methyl ethyl ketone and 1117 parts of isopropyl alcohol. And add 5 parts
The reaction was performed at 0 ° C. for 3 hours. The polyurethane resin solution E thus obtained has a resin solid content concentration of 30% and a viscosity of 10%.
It was 0 cP / 25 ° C. The number average molecular weight of the polyurethane resin was 8,000.

Production Example 6 In the same reactor as in Production Example 1, poly (1,2-propylene adipate) glycol 1000 having a molecular weight of 2,000 was added.
And a mixture of isophorone diisocyanate and 222 parts of isophorone diisocyanate. The mixture was reacted at 100 ° C. for 6 hours under a nitrogen stream to obtain a prepolymer having a free isocyanate value of 3.36%, and 815 parts of methyl ethyl ketone was added to obtain a uniform urethane prepolymer solution. Then isophorone diamine 74.2
In the presence of a mixture consisting of 13.5 parts of di-n-butylamine, 1222 parts of methyl ethyl ketone and 1019 parts of isopropyl alcohol, 2037 parts of the above urethane prepolymer solution was added and reacted at 50 ° C. for 3 hours. The polyurethane resin solution F thus obtained had a resin solid content concentration of 30% and a viscosity of 580 cP / 25 ° C. The number average molecular weight of the polyurethane resin was 25,000.

Production Example 7 1000 parts of poly (butylene adipate) glycol having a molecular weight of 2,000 and 222 parts of isophorone diisocyanate were charged into the same reactor as in Production Example 1, and reacted at 100 ° C. for 6 hours under a nitrogen stream to obtain a free isocyanate value of 3 .4
A 0% prepolymer was obtained, and 815 parts of methyl ethyl ketone was added thereto to obtain a uniform urethane prepolymer solution. Then, 49.3 parts of isophoronediamine, 14.5 parts of 2-hydroxyethylethylenediamine, 16.8 parts of di-n-butylamine, 198 parts of methyl ethyl ketone,
1013 parts of toluene and 10 parts of isopropyl alcohol
2037 parts of the urethane prepolymer solution was added in the presence of a mixture consisting of 13 parts, and reacted at 50 ° C. for 3 hours. The polyurethane resin solution G thus obtained had a resin solid content concentration of 30% and a viscosity of 790 cP / 25 ° C. The number average molecular weight of the polyurethane resin is 2000
It was 0.

Examples 1 to 5, Comparative Examples 1 to 30 30 parts of titanium white (rutile type), 50 parts of the polyurethane resin solutions A to G obtained in Production Examples 1 to 7, 10 parts of toluene,
Mixtures each having a composition consisting of 10 parts of isopropyl alcohol were kneaded with a paint shaker to prepare a white printing ink. To the obtained white printing ink, 35 parts of toluene and 15 parts of isopropyl alcohol were further added to adjust the viscosity, and eight white inks shown in Table 1 were produced. The white ink of Comparative Example 3 is a two-pack ink obtained by further adding 2 parts of isophorone dissocyanate to the white ink obtained in Comparative Example 1. The eight white printing inks were treated with a simple gravure printing machine equipped with a gravure plate having a depth of 30 μm using a discharge treated surface of a 15 μm thick corona discharge treated nylon film (NY) and a 11 μm thick polyethylene terephthalate (PET). Printing was performed on one side and dried at 40 to 50 ° C. to obtain a printed film. Then, a polyurethane adhesive having a solid content of 25% was applied on the printing surface of the obtained printing film at a coating amount of 3 g / m ² and dried, and then a 60 μm polyethylene film was dry-laminated with a laminator to obtain a laminated film. Was. The laminate strength (adhesive strength) of the laminate film thus obtained and the suitability for boiling at 100 ° C. were evaluated. Table 1 shows the evaluation results.

Boil aptitude (1) Evaluation by change in appearance of film The change in appearance of the laminated film after boiling at 100 ° C. for 30 minutes was observed. 〇-----There is no abnormality in the film. C: A part of the film is delaminated or blisters are generated. (2) Change due to lamination strength (adhesive strength) After boiling the laminated film at 100 ° C. for 30 minutes, cut it into a width of 15 mm and cut it at a speed of 300 mm with a peeling tester.
The T-peel strength was measured per minute and compared with the strength before boiling. (Unit g / 15mm)

[0035]

[Table 1]

[0036]

According to the present invention, the printing material has excellent adhesiveness to various plastic films such as polyester, nylon film, polyethylene and polypropylene as well as excellent boil resistance and storage stability. ,
A great effect is obtained that a printing ink binder that can be used as a one-pack type printing ink composition can be obtained.

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-4-63877 (JP, A) JP-A-3-177467 (JP, A) JP-A-2-99537 (JP, A) JP-A-5-95 295275 (JP, A) JP-A-5-271598 (JP, A) JP-A-5-331401 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C09D 11/00-11 / 20 C09D 175/00-175/16

Claims (2)

(57) [Claims] 1. A polymeric polyol, diisocyanate compound, in the printing ink binder composed mainly of a polyurethane resin obtained by reacting a chain extender and optionally a chain length terminator, the formula in the polyurethane resin
(1): ## STR1 ## [Wherein R ¹ and R ² represent a hydrogen atom, a halogen atom, a carbon number
1-20 alkyl groups, halogenated alkyl groups, oxy
Alkyl group, a phenyl group, or ^R 1, ^{R 2,} is bonded to
Shows those forming an alkylene group having 3 to 10 carbon atoms.
And R ³ is an amino group, a phenylamino group, a mercapto group
Printing ink binder, characterized in that it comprises an oxazolinyl group and / or a derivative of oxazolinyl group represented by the shown. 2. A polyurethane resin represented by the general formula (1):
Oxazolinyl group and / or the total amount of derivative of the oxazolinyl groups per polyurethane resin solids 1g are,
The printing ink binder according to claim 1, wherein the binder is contained in an amount of 1 × 10 ⁻⁶ to 1 × 10 ⁻³ gram equivalent.